The present invention relates to an image recording apparatus which records a color image on a recording medium under a given imaging condition.
Conventionally, there are three types of color copying machines which are of silver chloride photographing type, thermal transfer type and electronic photographing type. The silver chloride photographing type provides a high quality image, but it has shortcomings such that it takes a long time in making a copy and requires a high manufacturing cost as well as a high running cost per one sheet of copy. The thermal transfer type transfers three colors on a copying sheet in superposed manner and therefore has a low color reproducibility. The electronic photographing type is the quickest of all the three in making a copy and provides a high resolution; however, like the first type, it needs a high manufacturing cost as well as a high running cost due to increased cost of maintenance fee.
As a solution to the drawbacks of the above-described color copying machines, a new type of color copying machine has been proposed which provides a high color reproducibility, and is relatively inexpensive as well as easy to maintain. Such a color copying machine uses a photosensitive pressure-sensitive recording medium and sequentially forms latent images of three different colors, red (R), green (G) and blue (B), on the recording medium through light exposure. The recording medium on which the latent images are formed are brought into facial contact with a developer sheet and the latent images are developed under pressure to provide a visible image on the developer sheet. One of the methods for forming the latent images on the photosensitive pressure-sensitive recording medium is performed in the following manner. Individual images of red, green and blue colors are separately recorded as intermediate images on a thermal-sensitive sheet by means of a thermal head or the like. The thermal-sensitive sheet carrying the red image is first superposed on the recording medium, and the latter is exposed to light through or reflected from the thermal-sensitive sheet by means of a light source such as a fluorescent lamp. Then, the thermal-sensitive sheet carrying the red image is replaced by the thermal-sensitive sheet carrying the green image and exposure is similarly taken place to superpose the green latent image on the red latent image. Finally, the thermal-sensitive sheet carrying the green image is replaced by the thermal-sensitive sheet carrying the blue image and exposure similarly takes place to superpose the blue image on the red and green latent images. Thereafter, the recording medium is brought into facial contact with the developer sheet to pressure develop the latent images, whereby a visible full color image is provided on the developer sheet. Since the above-described method requires an intermediate image sheet on which images of three primary colors are separately formed, it is necessary to precisely position the intermediate images of each color component on the proper position of the photosensitive pressure-sensitive recording medium. In making a plurality of color copies, therefore, the same number of intermediate images for each color component should be prepared, thus requiring a large number of thermal-sensitive sheets and taking a long time to this effect. Furthermore, the image recording apparatus is made large in size manufacturing cost is increased.
As a solution to this problem, it has been proposed to separate the apparatus into an intermediate image recording apparatus and exposing/developing unit, in which an intermediate image sheet has been prepared in advance by the intermediate image recording apparatus, and the image sheet is placed on an original support stand of the exposing/developing unit and is exposed to light by the movement of this stand.
According to such an exposing/developing unit, since the order of placing the intermediate image sheets on the original support stand is designated depending upon the color of the intermediate images, if the intermediate image sheets are set in the wrong order, a desired color image will not be obtained.
Particularly, in the case where each of the intermediate images is formed on an individual cut sheet and those need to be placed on the original support stand one by one, attention should particularly be paid to set the cut sheets in the correct order as compared with the case where intermediate images of three colors are sequentially recorded on a continuous sheet.